This invention relates generally to wellbore casings, and in particular to wellbore casings that are formed using expandable tubing.
Conventionally, when a wellbore is created, a number of casings are installed in the borehole to prevent collapse of the borehole wall and to prevent undesired outflow of drilling fluid into the formation or inflow of fluid from the formation into the borehole. The casings are limited in length, often connected end-to-end by threaded connections.
Other inventions have disclosed a method of forming a wellbore casing that includes installing a tubular liner and a mandrel in the borehole, injecting fluid into the borehole, and radially expanding the liner in the borehole by extruding the liner off of the mandrel.
However, during the expansion, the tip ends of the threaded connections tend to peel away. The present invention is directed to overcoming this limitation of the expandable tubulars.